1. Field of the Invention
The present invention relates to a fire-retarding masonry lead-in fixture for cables, pipes and the like and having a housing including an axially extending through-bore, a radially protruding attachment flange provided at least at one end of the housing, and a mass intumescible in case of fire, with the mass limiting the bore at least regionwise and closing the bore upon being intumesced.
2. Description of the Prior Art
When planning and erecting buildings, in many cases, masonry lead-ins are left in walls and floors through which only in a later constructional phase or upon further development, pipes, cables and the like can be inserted. In this way, damage of the pipes, cables and the like in earlier constructional phases is prevented. To form, e.g., a masonry lead-in in a floor, already during the formwork work, a tubular fixture with a desired inner diameter, which serves as space retainer, is secured to the formwork and then is cast-in together with the concrete floor. The space retainer remains in the concrete floor and usually slightly projects above the floor at one side of the floor. However, the left lead-ins present a danger in case of a fire, facilitating its spread. Therefore, precautions should be taken to prevent the spread of fire through such lead-ins for a predetermined minimal period. To this end, the tubular fixtures includes primarily a fire-retarding mass which intumsces in case of a fire and, upon expansion, closes the lead-in. With an inserted combustible plastic pipe, the intumscent mass prevents the spread of fire through the pipe by crushing and closing the pipe upon being expanded.
For pipes, cables and the like having different outer diameters, respective tubular fixtures with corresponding inner diameters are provided as space retainers. Because dependent on a country, for a predetermined nominal diameter of a pipe, the effective outer diameters differ from country to country, it should be clear that a large number of lead-in fixtures with respective different diameters would be required for a pipe with the same nominal diameter. Furthermore, the inner diameters of tubular fixtures do not exactly correspond to the outer diameters of inserted pipes, cables and the like. Therefore, upon insertion, e.g., of a pipe, a more or less wide annular gap usually remains between the outer wall of the pipe and the inner wall of the fixture. It may also happen that a pipe or cable, which has a smaller diameter than that permitted by a fixture, is inserted through the fixture. The remaining gap enables an unhindered penetration of a smoke generated during a fire until the lead-in is closed with the intumescible mass. Therefore, with the conventional fixtures, the annular gap formed after the insertion of a pipe, cable and the like need be closed by using additional means. The gap is usually closed with mineral wool, mortar mass, a special sealing compound and the like. The expenses associated with the sealing of the gap increases with increased widths of the gap. Moreover, a substantially axial alignment of a pipe within the fixture becomes more difficult and is done with additional expenditure of time and labor. In the case when a lead-in in a wall or a floor is formed preliminary to a subsequent insertion of a pipe, cable or the like, which is effected in a later constructional phase, a conventional fixture requires a separate closure or cover for smoketight closing of the bore to a most possible extent.
Accordingly, an object of the present invention is a fire-retarding masonry lead-in fixture for pipes, cables and the like in which the drawbacks of the prior art are eliminated. The fixture should serve as a space retainer during the formation of a lead-in and have a greater flexibility with regard to the outer diameters of the insertable pipes, cables and the like. In addition, the fixture should insure an adequate smoke retardation, without any additional sealing, until the lead-in is closed with the intumesced-by-fire mass. It should be possible to eliminate additional smoketight closures or covers.